An improved solid-phase synthesis of resonance energy transfer fluorescent peptides and depsipeptides employing the EDANS/DABCYL donor-acceptor pair

Summary Fluorescent peptide substrates of the resonance energy transfer type, employing the donor-acceptor pair 5-[(2′-aminoethyl)amino]naphthalene sulphonic acid (EDANS) and 4-[[4′-(dimethylamino)phenyl]azo]benzoic acid (DABCYL), are widely used for continuous monitoring of the activity of various proteases. We describe here a flexible synthetic scheme which allows the synthesis of peptides having EDANS and DABCYL in any position of the sequence; the synthesis is entirely performed on solid phase with standard methods and makes use only of EDANS, DABCYL and commercially available amino acid derivatives. Moreover, we show that our scheme can be equally applied to the synthesis of EDANS/DABCYL-derivatised depsipeptides.